Board Thread:Pokémon Help/@comment-31267872-20170813174340/@comment-27535813-20170817080543

Don't ever run Fly in PVP, only a few users in PVP actually use it eg. Flynium Z Landorus-Therian set. It's a HM anyway so you can always put it back onto Charizard without any cost, or just get another Pokemon to be your HM user.